246 ORDER FLAGELLATA-PANTOSTOMATA. 



The circumstances under which the animalcules distinguished by the fore- 

 going title were first discovered by Mr. T. Richards Lewis, are so graphically 

 described by himself in the ' Quarterly Journal of Microscopical Science ' for 

 January 1879, tnat an abstract in extenso from that serial is herewith submitted. 

 Having been directed by the Indian Government to prosecute inquiries respecting 

 the Spirillum of Bombay fever, he remarks : " Whilst doing this I had occasion to 

 examine the blood of a considerable number of animals, and eventually (July 1877) 

 detected organisms in the blood of a rat, which at first sight I took to be of 

 the nature either of vibrions or spirilla. The blood, when transferred to the 

 microscope, appeared to quiver with life, but for some considerable time nothing 

 could be detected to account for this animated condition, as the blood-corpuscles 

 were somewhat closely packed. On diluting the blood with a half per cent, solution 

 of salt, motile filaments could be seen rushing through the serum and tossing the 

 blood-corpuscles about in all directions. Their movements were of a more undu- 

 latory character than are the movements of spirilla, and the filaments were thicker, and 

 more of a vibrionic aspect. They were pale, translucent beings, without any trace of 

 visible structure or granularity ; but as their movements were so rapid, exact informa- 

 tion as to their microscopical characters could not be ascertained at the time. The 

 slides were, therefore, placed under a bell-glass until these should diminish. 



" On the following morning the activity of the filaments was much less. Their 

 movements were more restricted and more undulatory in character, and the blood- 

 corpuscles, having become somewhat agglutinated, had apparently squeezed out the 

 organisms, so that the latter occupied the serum-areas of the preparations. After 

 watching their movements for some time under a Hartnack's No. 9 immersion 

 objective, it was observed that every now and then blood-corpuscles, some con- 

 siderably distant from any visible motile filament, would suddenly quiver. On 

 carefully arranging the light it was eventually observed that this movement was due 

 to the existence of a very long and exceedingly fine flagellum, apparently a posterior 

 flagellum, as the organisms seemed generally to move with the thicker end forwards, 

 the flagellum being seen following it, and lashing the fluid during the moment it 

 remained in focus. I have not been able to detect any flagellum at the opposite 

 end. They may sometimes be kept alive for two or three days, but generally the 

 greater portion will have died within twelve or twenty-four hours ; and not only 

 have died, but also disappeared from view. 



" When very carefully watched, the plasma constituting the thicker portion of their 

 substance may be seen suddenly to swell out at certain places, sometimes so as to 

 divide the ' body ' into two parts ; at other times two or three such constrictions and 

 dilatations may be detected, the dilatations being possibly observable only on one 

 side. At other times they assume an arrow-shaped aspect ; occasionally something 

 like granularity may be observed before their disappearance, but not a trace of them 

 is left after their disintegration. It seems as though they had been dissolved in the 

 serum in which they were found. I have examined the blood of a great number of 

 rats for the purpose of ascertaining what proportion of them contains these organisms 

 in their blood, and find that of those specially examined for this purpose, their 

 existence was demonstrated in 29 per cent. Sometimes, however, the number 

 detected were very few, not more than one or two in a slide, but in the greater 

 number of cases they were very numerous, every slide containing several hundreds." 



Mr. Lewis further remarks that the nearest approach to a description of these 

 haematozoa met with by him is contained in O. F. Biitschli's account of a flagellate 

 parasite obtained from the intestinal canal of the free nematode Trilobus gracilis.* 

 He -also gives quotations from Dr. Bastian's 'Beginnings of Life,' where, on the 

 authority of Dr. Gros, minute worms or " vermicules " are recorded to have been 

 observed in the blood of a field-mouse in such numbers as to cause the blood to 

 present an animated aspect, as also that the blood of the mole has been found 

 to exhibit a similar phenomenon. It is a remarkable circumstance that the rats 



* This form has been previously figured and described under the title of Lfplomonas Biitscklii. 



